For the past five years, the Minnesota Population Center has been engaged in a project to redesign the Integrated Public Use Micro data Series (IPUMS). IPUMS is a compatible series of large micro data samples of census and survey data spanning the period from 1850 to the present. Initially designed fifteen years ago, IPUMS is now one of the most widely used data sources in population research. This application seeks continued funding to support four areas of research and infrastructure development. 1) Database Expansion: IPUMS Redesign will incorporate the following files into the database as they become available: ACS and March Supplement of the CPS data, 2008-2012~ Puerto Rican censuses of 1910- 1930 and 1970-2000~ the Puerto Rican ACS~ and linked files for the CPS basic monthly survey, 1976 to the present. 2) Data and Metadata Improvement: Modernizing and upgrading the quality of IPUMS data and documentation is a top priority. IPUMS Redesign will support dozens of improvements, including: adding necessary clustering and stratification variables to allow reliable variance estimation~ enriching the machine- process able XML mark-up of the documentation~ and providing technical support and assistance to the Census Bureau to create IPUMS-compatible versions of all restricted-access census data from 1960 to 2000 for dissemination through Census Bureau Research Data Centers (RDCs). 3) User Support and Dissemination: IPUMS Redesign will continue to provide user support, training, and outreach and will harness the power and expertise of the IPUMS user community through a suite of web-based tools. 4) Data Access Infrastructure: IPUMS Redesign plans improvements in data access tools that will reduce researcher burden: consolidating multiple websites delivering U.S. census and survey micro data;allowing automated linking of micro data to summary file data and maps;providing enhanced variable search and retrieval;and improved online data analysis. The proposed expansion, improvement, and support of the database is directly relevant to the central mission of the National Institutes of Health as the steward of medical and behavioral research for the nation: IPUMS data are advancing fundamental knowledge about the nature of human population dynamics. Project Narrative IPUMS is a key component of American population and health data infrastructure. IPUMS Redesign will spark new health-related research on population growth and movement, fertility, mortality, and nuptiality, as well as the economic and social correlates of demographic behavior.